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Date: Fri, 14 Mar 2014 12:26:59 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PULL 125/130] target-ppc: Fix page table lookup
	with kvm enabled
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To: Alexander Graf <agraf@suse.de>, qemu-devel@nongnu.org, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexey Kardashevskiy <aik@au1.ibm.com>, Peter Maydell <peter.maydell@linaro.org>, qemu-ppc@nongnu.org, Greg Kurz <gkurz@linux.vnet.ibm.com>

Il 07/03/2014 00:34, Alexander Graf ha scritto:
> @@ -105,30 +106,37 @@ static target_ulong h_enter(PowerPCCPU *cpu, sPAPREnvironment *spapr,
>      if (!valid_pte_index(env, pte_index)) {
>          return H_PARAMETER;
>      }
> +
> +    index = 0;
> +    hpte = pte_index * HASH_PTE_SIZE_64;
>      if (likely((flags & H_EXACT) == 0)) {
>          pte_index &= ~7ULL;
> -        hpte = pte_index * HASH_PTE_SIZE_64;
> -        for (i = 0; ; ++i) {
> -            if (i == 8) {
> +        token = ppc_hash64_start_access(cpu, pte_index);
> +        do {
> +            if (index == 8) {
> +                ppc_hash64_stop_access(token);
>                  return H_PTEG_FULL;
>              }
> -            if ((ppc_hash64_load_hpte0(env, hpte) & HPTE64_V_VALID) == 0) {
> +            if ((ppc_hash64_load_hpte0(env, token, index) & HPTE64_V_VALID) == 0) {
>                  break;
>              }
> -            hpte += HASH_PTE_SIZE_64;
> -        }
> +        } while (index++);
> +        ppc_hash64_stop_access(token);

I'm afraid you have a bug here, as spotted by Coverity.  The do...while 
loop only loops once.  I'm not sure what you meant, could you rewrite it 
with a "for (index = 0; index < 8; i++)" instead?

Paolo